Chemelyne Sppecialities

Sampla, Rohtak, Haryana

Manganese promotes both 'surface dry' and 'through dry', although it is less efficient then cobalt and lead in air drying finishes. In baking finishes manganese is superior to cobalt as it does not cause imbrutement. Manganese also gives better result than cobalt in low temperature drying performance and does not suffer from wrinkling under high humidity conditions. However, manganese is rarely used along but added as a modifier, with cobalt being use as a primary drier. Manganese generally imparts a pinkyellow color to white enamels and hence is best avoided in such finishes. In some systems such as urethane oils, use of manganese in preference to cobalt results in reduced 'skinning' problems.

Zinc Octoate is an auxiliary drier used as a pigments dispersing agent. The pigment such as titanium dioxide and carbon black has the tendency to absorb driers which reduces loss or effect of drying rate. The absorption of driers in pigments can be reduced by grinding the pigments with Zinc Octoate to retain the drying capacity of the paint media. The preparation of paints based on high viscosity media which may have only limited solubility in the solvent employed, Zinc Octoate should be used before the addition of pigment as well as other drier combinations. Zinc Octoate prevents the paint film from webbing and frosting effects. The uses of Zinc Octoate is not suggested with dehydrated castor oil media and tong oil media because these driers may produce bloom and reduce gloss of the film.

Calcium is an auxiliary drier. It is used both in combination with lead and as a partial replacement for lead in vehicles that show poor tolerance for lead. Calcium prevents formation of basic lead phthalates in alkyds systems. When used along with zirconium in lead free systems, calcium driers find important application as pigment wetting agents and reduce loss of dry problems.